Corrosion inhibition in copper by isolated bacteria

Abstract

Purpose -The purpose of this paper is to report a study of microbiological influenced corrosion (MIC) of copper due to bacteria strains isolated from potable water pipes and oxidation lagoons using electrochemical noise (EN) analysis and scanning electron microscopy (SEM). Design/methodology/approach -Bacteria strains isolated from copper surfaces of potable water pipes and from oxidation lagoons were identified, based on the 16S rDNA gene sequence analysis. Corrosion studies were undertaken over a period of six weeks, placing copper electrodes inside an LB culture media with and without bacteria. The corrosion resistance was obtained using EN analysis. In all the cases, the corrosion type was identified. SEM images of the copper electrodes were taken to evaluate the surface condition. Findings -The bacteria strains identified were: Pantoea agglomerans, Alcaligenes faecalis, Bacillus cereus, Brucellaceae bacterium, Enterobacter cloacae, Delftia tsuruhatensis, and Pseudochrobactrum asaccharolyticum. EN analysis gave noise resistance values in the range 1,036-5,040 Vcm 2 for the control samples and in the range of 2,336-22,573 Vcm 2 for samples that had been inoculated with bacteria. It was found that a decrease in the rate of corrosion took place due to the development of a biofilm by the microorganisms on the copper surface. SEM images corroborated the presence of the biofilm on the copper electrodes. Practical implications -The isolated bacteria strain reduced the rate of corrosion on the copper electrodes, as shown by the SEM images and EN analysis results, due to the formation of a biofilm that can act as an anticorrosive coating. Originality/value -Even though MIC is a known phenomenon, it has not been reported that isolated bacteria strains can reduce corrosion on the surface of copper potable water pipes and in oxidation lagoons.

Biocorrosion control: Current strategies and promising alternatives

“…It was postulated that the exopolyssachrides produced by the bacterial strains reduced the corrosive activity as it prevented the interaction of the metal surface with the external environment. The protective action of the biofilms of P. fragi, E. coli and B. brevis as well as Actinomycetes has also previously been shown (Garcia et al, 2012). The presence of B. subtillis biofilms formed a protective layer allowing Al 2024 to be passive in artificial seawater (Zuo et al, 2005).…”

“…Therefore, the inhibitive effect of microbial biofilms is difficult to predict because biofilms in nature are not uniformly distributed and do not have uniform microbial activity (Lewandowski and Beyenal, 2008). However, Garcia et al (2012) showed, using Scanning Electron Microscopy and EN analysis that bacteria isolated form copper electrode surfaces prevented corrosion due to biofilm formation which acted as a protective anticorrosive coating (Garcia et al, 2012). It was postulated that the exopolyssachrides produced by the bacterial strains reduced the corrosive activity as it prevented the interaction of the metal surface with the external environment.…”

“…Dissolved oxygen, pH, total dissolved solids, temperature are few important factors. Oxygen dissolved in water is essential for the cathodic reaction to take place (Garcia et al, 2012). Low alkalinity waters that have little pH buffering capability can pick up acidic gases from the air and can dissolve metal and the protective oxide film on metal surfaces.…”

“…Corrosion is an electrochemical reaction between the environment and a material, generally a metal, which alters the properties of the material and impairs its function Garcia et al, 2012). Corrosion occurs spontaneously and can occur on most metallic materials.…”

“…It is an old and problematic industrial dilemma, and is the main cause of the failures of metallic structures (Askeland, 2004). Electrochemical corrosion entails the oxidation and dissolution of a zero valent metal, at a point known as the anode, and a subsequent reduction at the cathode involving an eternal electron acceptor (Juzeliunas et al, 2006;Garcia et al, 2012). In aerobic conditions, the cathodic reaction involved the reduction of oxygen, whereas in anaerobic conditions, the *Corresponding author.…”